1. Field of the Invention
Generally, the field of the present invention is laser stability. More particularly, the present invention relates to a resonator mounting assembly for isolation of resonator defining optics.
2. Background Art
Basically, a laser includes a gain or lasing media, a pumping device and a resonator. The pumping device provides energy that is absorbed by the gain media causing it to emits light from its opposite ends at the laser wavelength. The resonator is made up of resonator defining optics bounding the gain media such as in the form of two opposing mirrors positioned at the opposite ends of the gain medium and facing one another. Each mirror may be a single optical element or a combination of optical elements. The emitted light is reflected by the mirrors back through the gain media, which amplifies the emitted light as it is so reflected. One of the mirrors, called a high reflector, is fully light reflective, and the other, called an output coupler, is partially light transmissive.
The purpose of the two opposing mirrors is to reflect the light within the gain media until the light has been amplified to above an energy threshold condition that allows the light to measurably escape the output coupler. The light escaping from the output coupler is collimated, thereby passing a coherent laser beam of light traveling in a straight line and defining a laser beam propagation axis.
Other optical elements, such as a q-switch and polarizer(s), may be positioned between the output coupler and the corresponding one of the opposite ends of the gain media so as to share the propagation axis and assist in tailoring the reflecting light into a desired pattern for a given application.
Especially for applications requiring beam precision, the laser must remain highly stable. This requires that that the resonator defining optics, the gain media and other optical elements be maintained in co-alignment along the laser propagation axis over a large temperature range in order to generate a laser beam of the desired high quality and accurate beam pointing.
One approach to achieving laser thermal stability is disclosed in U.S. Pat. No. 6,081,544. This patent teaches the use of a stiff resonator structure to separate the mounting of the resonator defining optics on an underlying base from mounting of the gain media and other optical elements on the same base. The stiff resonator structure is mounted to the base via different support elements. One of the support elements, positioned at one end of the resonator structure, is a support foot that extends upward from the base, provides a rigid connection between the base and the resonator structure, and supports the one end of the resonator structure in an elevated position above the base. The other support elements positioned at the opposite end of the resonator structure are two identical flexure pieces that provide yieldable or flexible connections in a predetermined direction between the substrate and the resonator structure and support the opposite end of the resonator structure adjacent opposite corners thereof also in an elevated position above the substrate. The support foot and flexure pieces are made of the same material which is different from the material of the resonator structure and the substrate.